Fix crash when processing nested switch. (#2624)

* Fix crash when processing nested switch.

* Clean up.

---------

Co-authored-by: Yong He <yhe@nvidia.com>

1 files changed, 7 insertions, 4 deletions

diff --git a/source/slang/slang-ir-eliminate-multilevel-break.cpp b/source/slang/slang-ir-eliminate-multilevel-break.cpp
index 2330991c5..35412cc07 100644
--- a/source/slang/slang-ir-eliminate-multilevel-break.cpp
+++ b/source/slang/slang-ir-eliminate-multilevel-break.cpp
@@ -61,15 +61,19 @@ struct EliminateMultiLevelBreakContext
 
         void collectBreakableRegionBlocks(BreakableRegionInfo& info)
         {
+            // Push break block to a stack so we can easily check if a block is a break block in its
+            // parent regions.
+            breakBlocks.Add(info.getBreakBlock());
+            
             auto successors = as<IRBlock>(info.headerInst->getParent())->getSuccessors();
             for (auto successor : successors)
             {
+                if (!breakBlocks.Add(successor))
+                    continue;
                 if (info.blockSet.Add(successor))
                     info.blocks.add(successor);
             }
-            // Push break block to a stack so we can easily check if a block is a break block in its
-            // parent regions.
-            breakBlocks.Add(info.getBreakBlock());
+
             for (Index i = 0; i < info.blocks.getCount(); i++)
             {
                 auto block = info.blocks[i];
@@ -133,7 +137,6 @@ struct EliminateMultiLevelBreakContext
                     break;
                 }
             }
-
             for (auto& l : regions)
             {
                 l->forEach(